She understands her teacher perfectly, but because of a rare disability called Wolf-Hirschhorn Syndrome, she is unable to respond verbally.

The 14-year old speaks only a few short words, and until recently, her communication was limited to questions requiring 'yes' or 'no' answers.

Today, Caitlin responds to her teacher a different way.

"Hello, can I have your compost please?" comes a voice from an iPad, slung around her neck.

"Sure Caty, here you go."

Pushing another tile on the screen of her iPad, Caitlin responds: "Thanks".

Teachers at Henbury School in Darwin - where children must have an IQ lower than 70 to be eligible for enrolment - are raising money to buy iPads for many of their students who are verbally challenged.

Around 50 per cent of Henbury students now own iPads which they use in classes, with their peers in the playground and many at home with their families as well.

Ana Pethick says a range of iPad applications, including the speech program Proloquo2Go, are enabling students to overcome their speech barriers, and changing the realm of possibilities for their futures.

She says some parents raised concerns their children would become too dependent on the iPads, preventing them from any further speech development, but so far the results have only been positive.

"What we've seen is the complete opposite of that. We've seen their language develop - we think because they can listen to the words then repeat them. They are becoming more confident because they can practise," Ms Pethick says.

Caitlin's class teacher, Bev Grave, says Caitlin has taken to the iPad very quickly.

"Usually we just have to remind her to use her iPad, then she's fine, she goes around the whole school," Ms Grace says.

"This is enabling her to do things she wouldn't have been able to otherwise."

Maria Nistazou, 15, is another student who has adopted the iPad, having recently moved to Australian from Greece, with no knowledge of English.

Holding her iPad in its hardcase, Maria quickly navigates through screen displays to access programs that prompt her to guess the English names for different animals.

"We're using the iPad with Maria for language learning and interaction with her peers," teacher Anica Cormie says.

Maria sings a song in Greek to her TomCat application on the iPad, then waits patiently for it to sing back to her.

"That's actually taught her about turn taking, she didn't use to wait for the cat," Ms Cormie says.

"Maria has gone from knowing five words of English to, I don't even know how many, at least thirty, in the last 10 weeks."

So successful has the use of iPads been with Henbury students, that now some classes are run entirely through iPad communication, with direction from a teacher.

"If it is important for every child at Henbury to have an iPad, they will. It's just a matter of raising the money and rolling them out," Ms Pethick says.

In the mean time, Maria and Caitlin are happy to share their iPads with other students and enjoy the new shared point of interest and activity - something they have struggled to find at school for so long.